1. Field of the Invention
The present invention relates to a centering device for use with a machine tool, particularly for use with a lathe.
2. Description of the Prior Art
A conventional lathe includes a headstock having a chuck and a tailstock having a tailstock spindle. A work is held between the chuck and the tailstock spindle and is rotated by the headstock so as to be turned by a cutting tool. A clamp device is provided between the chuck and the tailstock spindle for clamping and centering the work during turning operation by the cutting tool while permitting rotation of the work. A clamping force of the clamp device is originated by a pressure medium such as a hydraulic fluid or a compressed air.
The clamping force applied to the work by the clamp device is, however, constant even if the diameter of the work has been changed or decreased through a turning operation. This may cause inaccurate centering of the work and therefore, it was difficult to precisely turn the work with the conventional clamp device.